i like very much MM, itunes has bugs & issues not yet fixed : at radio we switched to MM5 beta ; we needed aiff/flac and mp3/m4a support to organize our library & for dj'ing purposes.
atm i see and listed somes issues that need fixing :
- windows 10 desktop "api?" theme for UI reactivity/latency, too slow/buggy atm,
- saving a .M3U playlist dont recall last folder used for saving (x:\my music)
- on music tab : the separation line position between "genre / artist / album" panel and bottom "tracks" listing is not saved when relaunching MM5,
- auto-organize see duplicates where same track has different extension (mp3,m4a,AIFF,FLAC) : should rename even it's not same file-format,
voilà, i hope you will fix those issues asap : i know it's difficult actually but we got good hopes !
we plan to buy a gold license, so do you have a date (ETA..) on release date ?
we use MM5 professionally here

thx !